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(No Modl.) 2 Sheets-Sheet 1.

F. J. OSMOND.

' DRIVING MEC-HANISM FR BIGYGLES.

Patented Apr. 6, 1897.

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F. J. OSMOND. DRIVING MEGHANISM POR BIGYGLES.

Patented Apr. 6

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DRIVING MECHANISNI I-'OR BICYCLES.

SPECIFICATION forming part of Letters Patent No. 580,291, dated April 6, 1897. Application tiled December l, 18946. Serial No. 614,092. (No model.) Patented in England May 11, 1895, No. 9,389.

To all whom it mctyconccrn:

Be it known that I, FREDERICK JOHN Os- MOND,a subject ofthe Queen of Great Britain, residing at Moseley, England, have invented certain nenT and useful Improvements in the Driving Mechanism of Bicycles, Tricycles, and other Velocipedes, (for which I have obtained Letters Patent of Great Britain, No. 9,389, dated May ll, 1895;) and I do hereby declare that the following is a full, clear, and exact description of the invention, which will enable others skilled in the art to Which it appertains to make and use the same.

My invention has reference to such driving mechanism for bicycles, tricycles, and other velocipedes as consists of an interchangeable driving-chain ring secured to the ends of radial carrying-arms keyed on the crank-shaft; and my said invention consists of the improvements hereinafter described in connecting the said carrying-arms to the interchangeable driving-chain ring.

Bymyinvention a very efficient connection of the parts of this kind of driving mechanism is obtained, and the detachment of the said parts when necessary is readily effected.

My invention also permits of the use of unhardened interchangeable driving-chain rings with hardened radial carrying-arms.

According to my invention I make the driving-chain ring of such a sectional figure that one face of the said ring near its inner edge is provided With a projecting rib, equidistant gaps or openings being left in the said rib for the outer ends of the radial connecting-arms on the crank-axle to iit closely in. The ends of the gaps or cut-away parts in the rib of the chain-ring form shoulders or abutments for the edges of the radial arms fitted in the said gaps to bear against. The bottoms of the gaps or cut-away parts of the chain-ring rib are level with the face of the said ring, so that When the radial arms are introduced into the said gaps the parts of the arms extending beyond the said gaps bear against the flat face of the ring.

The inner edge of the chain-ring and its rib may be made slightly conical, and each of the radial arms has a shoulder the outer face of which may also be slightly conical, which shoulder on the arm when the latter is passed .into the gap in the rib of the chain-ring seats itself against the inner edge and rib of the chain-'rin g. i

The conical seatin gs or abuttin g parts of the shoulder and ring are ground, so that a very accu rate fittin g of the parts is secured. After the radial connecting-arms on the crank-axle have been fitted in their respective gaps in the chain-rings each of the said arms is held or bound in its place by a screw-pin passed from the unribbed side of the chain-ring through a large hole or clearance in the said ring and screwed into the extreme end of the arm. By thus connecting the radial arms on the crankaxle to the driving-chain ring the thrust of the said arms upon the said ring is borne only at the shoulders or abutments formed by the ends of the gaps in the rib of the chain-ring, there being no strain upon the chain-ring at the holding or binding screw-pins at the extreme ends of the arms in consequence of the size of the holes or clearances in the said` ring through which the said screw-pins pass.

Figure 1 of the accompanying drawings represents an elevation of the inner side of a driving-chain ring and combined crank and chainring carrying arms constructed and con'- nected together according to my invention. Fig. 2 represents a vertical section of the same, taken onthe line fr Fig. l. Fig. 3 represents an elevation of the outer side of a portion of the chain-ring and one of the carryingarms of the same. Fig. 4 is a section on the dotted line y y, Fig. 3. Figs. 5, 6, 7, and 8l represent the chain-ring and combined crank and radial chain-ring-carrying arms detached.

The same letters of reference indicate the same parts in the several figures of the drawings.

In constructing interchangeable drivingchain rings according to my invention I form on the outer face of each of the said rings a projecting annular rib or flange a, provided at the parts Where the chain-ring-carrying arms b b b are to be connected to it with gaps or unflanged parts a2 a2 a2, in Which gaps the ends of the said radial chain-ring-carrying arms b b b accurately fit, the edges of the arms when driving bearing against one or other of the shoulders or abutments a3 a3 at either side of the gaps a2.

The radial chain-ring-carrying arlns b b b are provided With curved shoulders b2 for tak- IOO ing a bearing against the inner side or edge of the driving-chain ring, (see Figs. 2, 3, and 4,) and thereby obtaining perfect concentricity in the iixing of the said ring to the radial arms. There thought necessary or desirable, the inner edge of the chain-ring may be made slightly conical, the outer or bearing sides of the curved shoulders b2 having a corresponding figure, the inner edge of the ring and the bearing side of the shoulders b2 being ground so as to accurately lit one another.

"When the interchangeable driving-chain ring is a-pplied to the radial chain-ring-carry ing arms Z9, screw-pins c c care passed through holes d4 a4 a4 in the face of the wheel into screwed holes b3 b3 b3 in the ends of the radial chain-ring-carrying arms b. It Will be seen by an examination of Figs. 2 ande that the holes a4 a4 a4 in the chain-ring are of a larger diameter than the stems of the screwpins o c c, so that on the driving of the chainring no shearing strain is put on the connecting screw-pins cc c, the pressure of the radial chainring-carrying arms b being borne solely by the shoulders or abutm ents d3 d3 of the rib or flange d, formed by the gaps a2 d2 @2in the said rib or flange d.

The bush of the combined crank and radial chain-ringcarrying arms is connected to the crank-axle in the ordinary Way.

Although I have shown my invention in connection With a combinedcrank and radial chain-ring-carrying arms, yet I Wish it to be understood that it is equally applicable to radial chain-ring-carrying arms Which are formed separate from the crank and are keyed independently to the crank-axle.

Having now particularly described and ascertained the nature of my invention and in what manner the same is to be performed, I declare that I claim as my invention of improvements in the driving mechanism of bicycles, tricycles, and other velocipedes- Interchangeable driving-chain rings having a rib or iiange a on one side and gaps or spaces a2, a2, a2 in the said rib or flange ci for the radial chain-ring-carrying arms Z), b, b, keyed to the crank-axle to take in and fit, the said arms Z), Z) having shoulders b2, b2, b2 for engaging under and iitting the inner side or edge of the chainring, the drivingchain ring being connected to the radial chain-ring-carrying arms by screw-pins c, c, c passing through large holes a4, a4, d4 in the chain-ring and taking in screwed holes b3, b3, b3 in the ends of the radial chain-ring-carrying arms ZJ, l, b substantially as and for the purpose herein set forth and shown.

' FREDERICK JOHN OSMOND.

Vitnesses:

RICHARD SKERRETT, ARTHUR JOHN POWELL. 

